Method of treating perishable onions in storage



Oct. 14,'1958 F. A. TEIGEN l METHOD'OF TREATING PERISHABLE ONIONS INSTORAGE Filed llarch 9, 1953 2 Sheets-*Sheet l INVENTUR.

7 Qu@ Attorneys METHOD OF TREATING PERISHABLE ONIONS IN STORAGE FiledIlarch l 9, 1953 F. A. TEIGEN Oct.A 14, 1958 2 Sheets-Sheet 2 owl? ALorhey's United States Patent O METHOD F TREATING PERSHABLE ONONS 1NSTORAGE Ferdinand Austin Teigen, Minneapolis, Minn., assigner to D, M.Russell, Minneapolis, Minn.

AApplication March 9, 1953, Serial No. 341,038 14 Claims. (Cl. 98--33)This invention relates to a method of preserving perishable onions instorage. In general the invention is concerned with the preservation ofonions, and other similar perishables in storage by the compounding andutilization `of a composite air of predetermined characteristics whichis introduced into the storage space and in intimate contact with theproduct to retard deterioration thereof.

This ,application is a continuation in part of my prior applicationSerial No. 2,153 tiled January 14, 1948, now abandoned.

In order to properly preserve `perishables, such as fresh onions, it isdesirable to circulate air into contact with the product, and it ishighly important to properly regulate both the temperature and themoisture content of the air. inhibit bacterial growth and yet not so lowas to cause freezing, and the moisture content should be high enough toprevent dehydration and yet not so high as to encourage the growth voflow temperature bacteria and/ or molds. As as example I have discoveredthat if dry onions are stored in an area Where the moisture content ofthe air is too low the Skin or hulls crack and loosen,

which results in reduction in commercial value.v Con-1 versely, if themoisture content of the air is toohigh,

tion through disease.

The temperature should be low enough to equally important and in fact iscritical at the time.

when it contacts the product. If the temperature is even a fraction of adegree too low, great damages may result from physiological shock anddisturbance of the metabolism of the product. In the case of onions andsimilar produce the optimum storage temperature is 32 F., and thereforethe air at the time of vcontact must be suiiiciently cool to preservethe product without freezing.

In the present invention it is proposed to provide a method ofpreserving perishable onions by withdrawing air from the storage spacein which the onions are situated and yforming or compounding `a returnor supply column of air which includes some of the withdrawn air and adiluent having a lower moisture content and/ or lower temperature, andforming a composite which is of the desirable temperature and moisturecontent for treatment of the perishable product to retard deterioration,and returning the composite thus formed into intimate contact with theonions in storage. 4

As perishables of the type mentioned are frequently grown and storedinareas having relativelyy cold winter climate, it will be appreciatedthat outdoor air may be used for refrigerating purposes, and also as asource of relatively dry air since the winter climate in the growingareas is generally below 32 F. and will therefore reduce the moisturecontent of the air. However, in the event that outdoor air is notsuiiiciently -dry and cool to be used in this invention in its existingcondition, any other source of dry, cool air may be used, in-

cluding all or a portion of the withdrawn air which has ice beensuitably processed or conditioned to give the proper low temperature andlow moisture content. In either event, dry cool air is used as a diluentof the return air. The condition of the dilution is measured, both astotemperature and humidity immediately before entry into the storagespace, and these measurements separately y and collectively are utilizedto control the compositing and treatment of the dilution to bring itwithin the desired limits.

An object of the invention is to provide a method of treating perishableonions to inhibit deterioration by circulating air having optimumtemperature and moisture characteristics into contact with the onions.

Another object is to preserve stored perishable onions by circulatingthe storage air and diluting the same with cooler and/or drier air whenthe temperature and/or the humidity of the circulated air returning tothe storage space is above a predetermined limit. Y u

Another object is to utilize cool dry air to provideonly a drying effector only a cooling elect, or both in pre# determined measure.

Another object is to control the moisture contentl of supply air byimparting heat to return air in conjunction with maintaining apredetermined dry bulb temperature by diluting the return air withdrier, cooler air from an convenient source. Other and further objectsof the invention willpended drawings 'disclosing an exemplary embodimentof the invention, in which:

Fig. l discloses a schematic representation of apparaf tus for treatingair which is utilized for treatment of perishable onions and the like,with a portion of the storage space broken away; and,

Fig. 2 is aside elevation of a portion of the structure shown in Fig. land a storage space in which the'perishables are. stored and treated inaccordance with the present invention. i' Referring to the appendeddrawings, which are schematic andv intended for illustrative purposesonly, gen` eral reference numeral indicates an enclosure, which as shownin Fig. 2 consists of walls 12, 14, 16, and18 that define a space withinwhich perishables such as onions may be stored. Enclosure 10 in itselfforms no part of the present invention and would be suitably deis aninlet air duct 24 that extends through one di mension of enclosure 10,and has a plurality of laterally extending branches 26, 28, and 32.While not shown, each ofthe branches are provided with small openingsfor discharging air under the false floor 20 where it may penetratebetween the slats and pass in intimate contact with the onions withinenclosure 10.

The inlet dnet24 penetrates wall 12 and is connected to apparatussituated outside of the enclosure 10, which will be describedhereinafter.

Also situated within enclosure 10 beneath the upper y wall 16 is areturn duct 34 which contains a plurality of openings 36, 38, 40 and 42for receiving air'from the enclosure and conducting the same outwardlythere. from. As is clearly shown, duct 34 also penetrates wall 12 and isalso connected to apparatus outside of en-` closure 10.

Referring now to Fig. 1, general reference numeral 44 be' apparent tothose skilled in the art upon a consideration of thefollowingdescription and claims, and in the ap-y f 3 indicates apparatus 'fortreating air which is used in this invention fortre'ating perishableonions within enclosure 10 to inhibit deterioration. A casing 46 issuitably connected to a fan casing 48. that contains a blower 50 driven.by ja motor "521' through 'suitable' 'connections' such as belts" 4?Theiblower'isprovided to draw air-'from casing' 63V 'and' passagesconnected thereto, and 'discharge the same into inlet *duct 24 in'sufficient volume to conmetall-ot'A the 'perishable onions withinenclosure 10. The return"duct34"extending -from'enclosure 10 is'suitably connected `jto casing' 46 at a part thereof spacedsubstantiallyl from the'inlet opening lin fan casing .48. Extendingfromduct 34 is a discharge duct S6, and at thefjunction ofthe's'e ductsis laA gravity'or pressure vcontrolledft"dar'np'er-tv whichpermitstdischarge of' air from duct "34;"4D`u'ct l56"'ordinarily'discharges to outsidey atmosphere, but, a's fw'ill be' *pointedi 'outhereinafter, when des'iredit may betconnected'to -suitable refrigerationvapparatus designated-Lat '59; which is provided with a damper 59a; f v

Also connectedto'casing 46is'a duct \6`0`andan extension 60awhich'eXtnds "from fa suitable source Vof drier, cooler lair;jInmany-instances' the-perishables with which thisinvention iisconcerned-tare ygrownin Northern regions where after harvest the outsideatmosphere 'isnaturally cooledfs ftcien't-to permitffitsuse as:zr-refrigeration medium.A Inder such conditions the :outside airwill'for long periods lof time -during thewinter months be at anaturalltemperatureof less than 32 Fiand consequently f its moisturecontentwill be relatively low; lf, however, thevprocesslofthis inventionisto `-bepracticed in areas whereA outside'v air is notsubs'tantially-below 32 F. and its moisture lcontent'is notfcorrespondingly low, thenby adjustmentohdamperf59a some=or fall of the air willbe drawn throughthe apparatus 59as-thef'sou'rce of drier,

cooler fair; A

At theinner terminal ends of du'cts '34and 607are dampers': 62v land l64that Iare interconnected by a linkage shown in dotted lines at 66.' i'SA -rnotor68 of modulating or springireturn type is -conn'ected to a`linkage 70 that is Ajoined'ltoflinlrage' 66. Dampers 62,l 64 areprovided to control yflowoffair 'withdrawn 4from enclosure 10 yand alsothe supply of dry cool air, which hereinafter' 'will be referred `toasfadiluent'fof/the withdrawnair, regardless of the amountlof aircontributed 'respectively` by ducts 34 and60 to'form a composite airthat is the 'source of supply air returned `through duct/Mitotheenclosure 10.

A source oftheat, :herelshownin the form of a' serpentine `coil r'LtV isprovided tofim'paztlheat Lto the A'supply lair.'

Coil 72 V is :shown within the outletI orzreturn-air Lduct 34, but`thisisfa mere matter of onveniencelandif 'desired it .may :by .suitable`adaptationbe` situated-Swithin lthe" casingf4 6," sinceheatris-rimparted towolum'etrically iincrea'se'the diluent and notsubstantially .raise the temperature of the'dilution, whichis returnedto the enclosure." An inlet conduit 74 `is joinedto one 'endof coil l72and.

contains'a suitable =c0n`trol"device, here shown as a motorizedmodulating lvalve 76. An outlet yconduit 7S extends from vthe other endof coil 72. Conduit 74,

whil'e not shown; extends from a suitablefsource of steamY or lhotwater. If either: of these sources `of heat are not available, tanyother :suitable source of heat may lbe used.

Situated-inthe :supply:.duct V24 is kfa' Athermostat 110 Which'is-responsive'to the dry 'bulb temperatureof supply air ordilutionrreturning tofenclo'surel. Thermostatmodulatingmovementof-motor68 in either direction, in

response to changes '-in temperature of 'supply air to apportiontheproportions of withdrawn `air'and diluent ente'ri-ngcasing V46.

Also situated in the supply duct 24 is a humidis'tat 114 which isresponsive to the humidity of the enveloping supply air or dilution.`Hurnidstat 114 is 'connected by a cable 116 to valve 76 and contains aplurality of wires depending on the type of control device used.Preferably, valve 76 may be modulated between its open and closedpositions.

The process will now be explained in connection with its use fortreating onions: During or just after harvesting, the onion bulbs aretopped at their necks and they are preferably placed in the storagespace in a bulk condition. 1Eer a period of six weeks two months thebulbs undergo a curing process Ain which they are maintained at atemperature of between 50 and 60 F., and an atmosphere whose relativehumidity is 'substantially 70%. The curing process is a biologicalprocess in which wounds heal and the necks of the bulbs seal themselves,and the outer skin tightens around the bulb. The present apparaus isused during the curing process to treat the onions tobe dryandof'desired temperature by envelopme'nt "with air -of"^requiredtemperature and moisture content'moving at relatively `high. velocity todissipate heat Vand moisture evolved through respiration which if notdissipated, promptly creates deleterious conditions YpredisposingItorapid "deterioration, At 'the g conclusion of the primary -'curingprocess the-apparatus is adjusted by reducing and maintaining the supplyair temperature "at about 32h91?. with 'the relative humidity remainingat 70%.- The airsforcibly circulatedthr'ough the onions at a sufficientpressure so that it willmove laterallyas well as vertically A"through'the :mass and thus come into intimate contact-with the surface-of 'allof the onion bulbs. In'the"followingflexamples the process will beexplained in vconnection-with Y the maintaining 'process rather than theinitial curing` although it should be understood that 'the steps aresubstantiallyidentical.v

With the parts 'disposedfas shown in the drawing, and fan' 50 inloperation, air is circulated from v*room 10 through duct 34 Vto Aandthrough -the fan yand thence `through duct 24, and itsnufmerousf'branches-to and For storage :purposes thermostat through the"product. is adjusted -to cause motor 685to''simulta-"neouslyr opendamper 64 and clo'sedan1p`er62asfthe-dry-bulb vtemperatur'e of supplyairvrises above 32 -FQ- 4Humidis'tat i114 is set to open valve 76 andvadmit steam `toithe coil 72 when fthe relative humidity'of airreturnin'gfthroug'h duct 24, is greaterl than 70% or any otherpredetermined setting.

Assuming the supply air returning 4'to enclosure 10 has a dry bulbtemperature `ofi32" 'F.anda rel'ativehumidity of 70%, the only actionwhich is'taking place `is the mere circulation of air. -In the `earlystages-of -the storage treatment-1 the air will be absorbing @heat andmoisture fromlthe onionsfand under-this condition thermostat 1l@ willrespond to the rise in air temperature and energize motor68 tof'causedamper 16E-to move toward a closed position and' damper 64 to move'toward an open positionl- When this occurs, and assuming duct 60Yto bein communication'with 'dry'.cool air, the latter will he drawn lintoVfca'sing 46Y Sto dilute the withdrawn air and reduceltemperaturethereofto the degree l'setting of thermostat 1.10; And because the'supply airunder 'the stated situation @may contain more than 70%lrelative humidity, Jhumidstat .M4V will in `such 'caseV respond t0 thehigher V.moisture fconte'ntof the air, causin'gvalve 76 to move to anopen position admittingfsteam to coil 72 to therby -heat 'the withdrawnlair. As was explained heretofore, it is not essentialthat heater 72 besituated in Vduct -34"-`since litcouldwith` equal useful-ness be incasing46- The 'purpose 'and result 'of adding V'heat 'tothe withdrawn'air Lor dilution is to`inc'rea`se the proportion of diluerit,f since anyheat added to the dilution will be sensedbyY thermostat 110, which-'will cause motor 68 to be further actuated to increase the proportionvof the dry, cool diluent It has vbeen emphasized-heretofore that motor68` and valve 76"are operated by"modul'atin`g mechanisms and, therefore,as the proportion of diluent is increased the density of water vapor inthe supply will be decreased to a point where thedampers 62 and 64 andvalve 76 assume a co-relative position comprising a balanced condition,to supply a dilution of desired characteristics. Since air is beingadded to the total volume within the enclosure 10, a pressurizedcondition vwill form and damper 58 will move to a partly open positionto permit discharge of a volume of air equal to that introduced throughthe duct 60.

After the storage process has proceededfor some time, the temperature ofthe withdrawn air will drop, and as a second condition it is assumedthat thermostat 110 is satised, but humidistat 114 is still respondingto a condition of excessive moisture in the supply air. Under theseconditions valve 76 willgradually be opened to admit steam to heater 72,which in turn will affect thermostat 110 to the extent of admittingdiluent through damper 6'4 from duct 60 to reduce the humidity ormoisture content of air entering enclosure 10 and varying admission ofdiluent in ratio to variations in the admission of steam and thepressure thereof in heater 72 to a point of establishing balance betweenproportion of diluent and desired density of water'vapor in dilution.

In the event that the outdoor or fresh air is above the desired limitsof temperature and/ or humidity, the damper 59a is adjusted to thedotted line position to draw air either from the outer end of duct 56 orfrom duct 34 past da-mper 58, or both, whence such air passes to andthrough the refrigerating apparatus 59, whereby its moisture and heat isreduced below the desired maximum, whereafter the dehumidified airpasses into duct 60 and thence into casing 46 in the proportiondetermined by dampers 64 and 62. For the purpose of the presentinvention, it'is considered that duct' 60 is connected at all times witha source of air of required temperature and humidity, which is airhaving a dew point and dry bulb temperature substantially lower than theconcurrent dew point and dry bulbvtemperature of the air within theenclosure.`

The advantages of my invention reside in the provision of methods totreat and apportion component airs to compose a composite providingthenecessary psychrometric conditions for the instant treatment ofperishable onions to aid intheir better cure and preservation.

l. .The method of preserving and/or curing onions which includesconfining fresh perishable onions for treatmentwith conditioned airwithin a substantially airtight insulated enclosure; heating andadmitting rair from said enclosure into a mixing chamber; admitting fromthe outside into said mixing chamber fresh air having a dew point anddry bulb temperature substantially lower than the concurrent dew pointand dry bulb temperature of the air within said enclosure; mixing saidfresh air with said heated air; forcing the resultant mixed air fromsaid mixing chamber into contact with and through said onions during theperiod that said onions are confined for treatment in said enclosurewhen the temperature of said onions is outside the degree of temperaturefixed as the concurrently desired temperature of said onions and/or therelative humidity of the air within said enclosure is` more than 70%,until the temperature of said onions is of said fixed degree and therelative humidity is less than 70%; discharging superfluous air fromsaid enclosure to the outside; andregulating the dew point and dry bulbtemperature of said mixed air when forced into initial contact with saidonions by varying the-heating' of said he'ated air which is mixed withsaid fresh air in accordance with changes in the relative humidity ofsaid mixed air Vprior to contact between said mixed air and said onions,

and concurrently varying `the volume of said fresh air which is mixedwith said heated air in accordance with changes in the capacityof saidheated air to heat the lfresh air contained in the 4resultant mixed airto the de'- gree of temperature fixed as the desired temperature of'said mixed air when forced into initial contact with said onions.

2. The method of preserving and/or curing onions which includesconfining fresh perishable onions for treatment with conditioned airwithin a substantially airtight insulated enclosure; heating andadmitting air from said enclosure into a mixing chamber for mixture withfresh air to provide air having a dry bulb temperature substantiallyhigher than the concurrent tempe-rature of the air Within saidenclosure; admitting from the outside into said mixing chamber fresh airhaving a dew point and dry bulb temperature substantially lower than theconcurrent dew point and dry bulb temperature of the air within saidenclosure; mixing said fresh air with said heated air; forcing theresultant mixed air from said mixing chamber into contact with andthrough said onions during the period that said onions are confined fortreatment in said enclosure when the temperature of said onions isoutside the degree of temperature fixed as the concurrently desiredtemperature of said onions and/ or the relative humidity of the airwithin said enclosure is more than until the `temperature of said onionsis of said lixed degree and the relative humidity of said air is lessthan 70%; discharging superuous air from said enclosure to the outside;and varying the volume of said fresh air which is mixed with said heatedair in accordance with changes in the capacity of said heated air toheat the fresh air with which it is mixed to the degree fixed as thedesired temperature of ysaid mixed air when forced into contact withsaid onions to thereby regulate said temperature of said mixed air.

3. The method of preserving and/or curing onions which includesconfining fresh perishable onions for treatment with conditioned airwithin a substantially airtight insulated enclosure; admitting air fromsaid enclosure into a mixing chamber; Iadmitting from the outside intosaid mixing chamber fresh air having a dew point and dry bulbtemperature substantially lower than that of said air admitted from saidenclosure; mixing said fresh air with said air admitted from saidenclosure; imparting heat to the resultant mixed air; forcing theresultant heated mixed air from the mixing chamber into Contact with andthrough said onions during the period that said onions are confined fortreatment in said enclosure when the temperature of said onions isoutside the degree of temperature fixed as the concurrently-desiredtemperature of said onions and/or the relative humidity of the airwithin said enclosure is more than 70%, until the temperature of saidonions is of said fixed degree and the relative humidity of said air isless than 70%; discharging superuous air from said enclosure to theoutside; and regulating the dew point and dry bulb temperature of saidmixed air when forced into initial contact with said onions by varyingthe amount of heat imparted to said mixed air in accordance with changesin the relative humidity of said mixed air subsequent to saidimpartation of heat thereto and prior to contact with said onions, andconcurrently varying the volume of said fresh air which is mixed withsaid air admitted from said enclosure in accordance with changes inthecapacity of the heat imparted to said mixed air to heat the fresh aircontained in said mixed air to the degree of temperature fixed as theconcurrently desired temperature of said mixed air when forced intoinitial contact with said onions.

imparting-heat to the resultant mixed air; forcing theV resultantrheated-'mixed' air from -said mixing chambery into contact with andthrough said onions during 'the relative humidity of the air within saidenclosure 'is lmore than 70%, until the temperature -of said onions isof said fixed degree and the relative humidity of said' air is less than70%; discharging Vsuperfluous-air from said enclosure to the outside;and varying the Volume of said fresh air which is mixed 'with said airadmitted from said enclosure in accordance with changes iin -capacity ofthe heat impartedto said mixed air toheat the-fresh air contained insaid mixed air to the degree of temperature fixed as the -`concurrentlydesired temperature of said mixed air vwhen forced into initial contactwith said onions and thereby regulating said temperatu're'of said mixedair.

5, The method of preserving and/or curing onions which includesconfining freshy perishable onions .for treatment with conditioned airwithin a substantially airtight insulated enclosure; heating andadmitted air from said enclosure into a mixing chamber; admitting airinto said mixing chamber which air prior to admission into said mixingchamber is conditioned to have and has a dew point and dry `bulbtemperature substantially lower than the concurrent dew point and drybulb temperature of the air within said enclosure; mixing saidconditioned air with said heated air; forcing the resultant mixed airfrom said chamber into contact with and through said onions during theperiod that said onions "are confined for treatment in said enclosurewhen 'the temperature of said onions is outside the degree oftemperature fixed as the concurrently desired temperature of said onionsand/or vthe relative humidity of the air within said enclosure is morethan 70%, until the temperatureof said onions is of said fixed 'degreeand the relative humidity of said air is less than 70%; dischargingsuperfluous air from said yenclosure to the outside; and regulating thedew point and dry bulb temperature of said mixed air when forced fromthe mixing chamberinto initial contact with said onions by varying theheating `of said heatedair which is mixed with said conditioned air inaccordance with changes in the relative humidity of said mixed airsubsequent to the impartation of heat thereto and prior to'conta'ctbetween said mixed air and said onions, and concurrently varying the'volume of said conditioned air which is mixed with lsaid heated air inac corda'nce with changes Tin the c'apa'city fof vsaid heated air to'heat the conditioned fair with 'which it is mixed to thedegree xedasthe concurrently desired temperature of* saidmixed lair when 'forced'into initial contactV with said yonions.4

6. The method of 'preservingand/or curing onions which includesconfining fresh perishable onions for treatment with conditioned airwithin' a substantially airtight insulated enclosure; yheatingandadmitting air from said enclosure into a mixingichamber;admittingfairinto saidfmixing-chamber which air 'prior to Iadmissioninto said mixing'chamber is conditioned to have and has a dew point and dry bulbtemperaturevsubstantially lower fixed as the concurrently desiredtemperature-of -said onions and/or the`relativehurnidity`of the airwithin humidity fof-said -airis less than 70% discharging superliuousair from said enclosure to theoutside; and varying thervolume of -saidconditioned air which is mixedl with saidiheated air in accordance withchanges in the.

capacity -of said heated airf to heat the conditioned air with whichit.is mixed to the degree fixed asthe concur` ,rently desired `temperatureof said mixed air when forced into contact with said onions to therebyregulate said desiredxtemperaturetof said mixed air.

7. The method ofA preserving and/or curing onions which includesconfining fresh perishable onions fortreatment with conditioned airwithin a substantially airtight insulated enclosure; admitting air fromsaid enclosure into a mixing chamber; admitting air into vsaid mixingchamber ywhich yair prior to admission into said mixing Y chamberisconditioned to have and has a `dew point and dry bulb temperaturesubstantially: lower than Athe concurrent dew point and dry 'bulbtemperature ofthe air 'within said enclosure; y.mixing said conditionedlair with the air admitted frornsaid enclosure; imparting heat to theresultant mixed air, forcing the resultantheated mixed -air from-:themixing chamber into contact .-with and through -said onions vduring theperiod that saidA onions are confined for treatment in said enclosurewhen the temperatureofsaid onions is outside the degree of temperatureiixed as the concurrently desired temperature of said onions land/or therelative humidity of ythe air withinsaid enclosure is more than 70%,until the'tem- Y peraturev of said onions is of said fixed degree andtheV relative humidity -of said air is less than 70%; dischargingsuperiiuous air from said enclosure tothe outside; i

and regulating the dew point and dry bulb temperature of said mixed airwhen forced into initial contact' with` said onions :by varying theamount of heat imparted -to said mixed -air in accordance with changesin the relative humidityr of said mixed air subsequent to saidimpartation of heat thereto and prior to contact between said mixed4Vair and said onions, and concurrently varying 4the volume ofconditioned air which is mixed with the air admitted from said enclosurein accordance with changes in the capacity of the heat imparted to saidmixed air to heat the conditioned air contained in said mixed air to thedegree of temperature fixed as the concurrently desired temperature ofsaid mixed air when forced into initial contact with ysaid onions.

8. The method of 'preserving and/or curing onions" pointand dry bulbtemperature substantially lower than the concurrent dew point and drybulb temperature of the air within said enclosure; mixing saidconditioned air withtheair admitted from said enclosure; imparting heattothe resultantmixed air; forcing the resultant heated' mixed Yair fromsaid mixing chamber into contact with f" and through saidlonionsduring'the period that ksaid onions are confined for treatment in 'saidenclosure when the' temperature of said onions is outside the degree of:temperature Vfixed ias .the concurrently desired vtemperature of saidonions and/or the :relative humidity ofthe fair withinsaid enclosureismore than'70%, until the temperatu'reof said onions is of vsaid iixeddegree and the relative humidity of said air is less than 70%;discharging 'superfluous air from said enclosure to thefoutside;VV

and varying 'the volume of conditioned air which "is mixed with said'air admitted from said enclosure -in accordance with the capacity ofthe heat imparted to said mixed air to heat the fresh air contained insaid mixed vair to the degree of temperature fixed as the consurrentlydesired temperature of said mixed air-When forced into initialcontactwith said onions and=thereby regulatingsaid temperature of saidmixed air.'

9. The methodsof-L preserving and/or l-curin'g 'onions 1 which includesconfining fresh perishable onions for treatment with conditioned airWithin a substantially airtight insulated enclosure; heating andadmitting air from said enclosure into a mixing chamber; admitting fromthe outside into said mixing chamber fresh air having a dew point anddry bulb temperature substantially lower than the concurrent dew pointand dry bulb temperature of the air within said enclosure; mixing saidfresh air with said heated air; forcing the resultant mixed air from themixing chamber into contact with and through said onions during theperiod that said onions are confined for treatment in said enclosurewhen the temperature of said onions is outside the degree of temperaturefixed as the concurrently desired temperature of said onions and/or therelative humidity of the air within said enclosure is more than 70%,until the temperature of said onions is of said fixed degree and therelative humidity is less'than 70%; discharging superfluous air fromsaid enclosure to the outside; and regulating the dew point and dry bulbtemperature of said mixed air when forced into initial contact with saidonions by varying the heating of said heated air which is mixed withsaid fresh air in accordance with changes in the relative humidity ofsaid mixed vair under the control of the relative humidity of said mixedair prior to contact between said mixed air and said onions, andconcurrently varying the volume of said fresh air which is mixed withsaid heated air admitted from said enclosure in accordance with changesin the capacity of said heated air to heat the fresh air contained inthe resultant mixed air to the degree of temperature fixed as theconcurrently desired temperature of said mixed air under the control ofthe dry bulb temperature of said mixed air subsequent to the formationthereof and prior to contact between said mixed air and said onions.

10. The method of preserving and/or curing onions which includesconfining fresh perishable onions for treatment with conditioned airwithin a substantially airtight insulated enclosure; admitting air fromsaid enclosure into a mixing chamber; admitting from the outside intosaid mixing chamber fresh air having a dew point and dry bulbtemperature `substantially lower than that of said air admitted fromsaid enclosure; mixing said fresh air with said air admitted from saidenclosure; imparting heat to the resultant mixed air; forcing theresultant mixed air from said mixing chamber into contact with andthrough s'aid onions during the period that said onions are confined fortreatment in said enclosure when the temperature of said onions isoutside the degree of temperature fixed as the concurrently desiredtemperature of said onions and/or the relative humidity of the airwithin said enclosure is more than 70%, until the temperature of saidonions is of said fixed degree and the relative humidity is less than70%; discharging superfluous air from said enclosure to the outside; andregulatthe dew point and dry bulb temperature of said mixed air whenforced into initial contact with said onions by varying the amount ofheat imparted to said mixed air in accordance with changes in therelative humidity of said mixed air subsequent to the impartation ofheat thereto and. prior to contact between said mixed air and saidonions under the control of said relative humidity of said mixed air,and consurrently varying the volume of said fresh air which is mixedwith lsaid air admitted from said enclosure in accordance with changesin the capacity of the heat imparted to said mixed air to heat saidfresh air contained in said mixed air to the degree of temperature xedas the concurrently desired temperature of said mixed air under thecontrol of the dry bulb temperature of said mixed air when forced intoinitial contact with said onions.

l1. The method of preserving and/or curing onions which includesconfining fresh perishable onions for treatment with conditioned airwithin a substantially airtight Minsulated enclosure; admitting air fromsaid enclosure into a mixing chamber; admitting into said mixing ber airhavingv a dew point and dry bulb temperature substantially lower thanthe concurrent dew point and dry bulb temperature of the air within saidenclosure; mixing said colder air with the warmer air admitted from saidenclosure; heating at least one of the components of said mixed air;forcing the resultant mixed conditioned air from the mixing chamber intocontact with and through said onions during the period that said onionsare confined for treatment in said enclosure when the temperature ofsaid onions is outside the degree of temperature xed as the desiredconcurrent temperature of said onions and/or the relative humidity ofthe air within said enclosure is more than 70%, until the temperature ofsaid onions is of said fixed degree and the relative humidity of saidair within the enclosure is less than 70%; discharging superfluous airfrom said enclosure to the outside; and varying the volume of the colderair which is admitted into said mixing chamber and mixed p therein withwarmer air from said enclosure in accordance with changes in thecapacity of the heat available to heat said colder air contained in saidmixed air to the degree of temperature iixed as the concurrently desiredtemperature of said mixed air, and concurrently varying the impartationof heat to at least one component of said mixed air in a measure wherebythe dew point of said mixed air is lower than the concurrent dew pointof the air within said enclosure when said mixed air is forced intoinitial contact with said onions.

12.' The method of curing onions which includes confining freshlyharvested uncured onions for treatment with conditioned air within asubstantially airtight enclosure; admitting air from said enclosure intoa mixing chamber; admitting into said mixing chamber air having a dewpoint and dry bulb temperature substantially lower than the concurrentdew point and dry bulb temperature of the air within said enclosure;mixing said colder air admitted into said mixing chamber with the airfrom said enclosure; heating at least one of the cornponents of saidmixed air; forcing the resultant mixed conditioned air from the mixingchamber into contact with and through said onions during the period thatsaid onions are confined for treatment in said enclosure when thetemperature of said onions is substantially outside the range of 50F.-60 F, and/or the relative humidity of air within said enclosure ismore than 70%, until the temperature of said onions is substantially 50F.60 F. and the relative humidity of the air within said enclosure isless than 70%; discharging superfluous air from said enclosure to theoutside; and varying the volume of the colder air which is admitted intosaid mixing chamber and mixed with the air admitted into said mixingchamber from said enclosure in accordance with changes in the capacityof the heat available to heat said colder air contained in said mixedair to the degree of temperature fixed as the desired temperature ofsaid mixed air and concurrently varying the impartation of heat to atleast one component of said mixed air in a measure whereby the dew pointof said mixed air is lower than the concurrent dew point of the airwithin said enclosure when said mixed air is forced into initial contactwith said onions.

13. The method of preserving cured onions which includes confining freshperishable cured onions for treatment with conditioned air within asubstantially airtight insulated enclo-sure; admitting air from saidenclosure into a mixing chamber; admitting into said mixing chamber airhaving a dew point and dry bulb temperature substantially lower than theconcurrent dew point and dry bulb temperature of the air within saidenclosure; mixing said colder air admitted into said mixing chamber withthe air admitted from said enclosure; heating at least one of thecomponents of said mixed air; forcing the resultant mixed conditionedair from said mixing chamber into contact with and through said onionsduring the period that said onions are conneid for treatment insaidenclosure when the temperature of said onions is `above freezing and at'substantial Variance rfrom-32 and/or the 'relative humidityof theairwithin said enclosure is more ,than 70%, until the temperature of saidonions is substantially 32 F. and :the relative thumidity of the airwithin said enclosure Vis vless than 70%,; discharging super.- uous air,from said enclosure to the outside; and varying the volumeof the colderair which is admitted into said mixing chamber and mixed with the airadmitted 4fromsaid enclosure in accordance with changes in the capacityof the heat available to heat said colder air contained in said mixedair to the degree of temperature xed as the concurrentlydesiredtemperature of said mixed air, and Yconcurrently varying theirnpartation of heat to at least one componentV of said mixed air in ameasure whereby the dew point `of said mixed air is lowerthan theconcurrent dew point of the air within said enclosure when said mixedair is. forced into initial contact with said onions.'

14. The method vo'fpreserving and/or curing lonions which includesconiining fresh perishable onions for treatment with conditioned airWithin a substantially airtight insulatedV enclosure; admitting airfromsaid enclosure l into a `rnixing'chamber; 'admitting Tinto said mixingcharnber air having adewY point and dry bulb temperature substantiallylower than the concurrent dew point and dry bulb temperatur-e201? the.air within said enclosure; mixing said colder air with'the warmer airadmitted from said enclosure; .heating atleast one of the components ofsaid'mixedairg'forcing the resultant mixed conditioned air from themixing chamber into contact with and through said-onions .during theperiod thatsaid onions are.'

conned'for treatment in said enclosure when the temperature .of saidonions is outside-the degree of temperature xed as the desiredconcurrent temperature of said onions and/ or the relative humidity ofthe air within said enclosure is more than until the temperature of said.onions is of said fixed degree and the relative humidity of'said airwithin theenclosure is less than 70%; dischargingV superfluous air fromsaid enclosure .to the outside; and regulating the relative humidity anddry bulb temperature of said mixed air when rforced into initial Contactwith said onions by varying the proportions of said colder and saidwarmer air in said mixed air and the heating of at least one of said aircomponents in t accordance with changes in the condition of said mixedair subsequent to the impartation of heat to atleast one componentthereof and prior to contact between said mixed air and said onions.

References Cited Yin the tile .of this patent UNITED STATES PATENTS

